It is highly desirable for tires to have good wet skid resistance, low rolling resistance, and good wear characteristics. It has traditionally been very difficult to improve a tires rolling resistance without sacrificing its wet skid resistance and traction characteristics. These properties depend to a great extent on the dynamic viscoelastic properties of the rubbers utilized in making the tire.
In order to reduce the rolling resistance of a tire, rubbers having a high rebound have traditionally been utilized in making the tires tread. On the other hand, in order to increase the wet skid resistance of a tire, rubbers which undergo a large energy loss have generally been utilized in the tires tread. In order to balance these two viscoelastically inconsistent properties mixtures of various types of synthetic and natural rubber are normally utilized in tire treads. For instance, various mixtures of styrene-butadiene rubber and polybutadiene rubber are commonly used as a rubber material for automobile tire treads. However, such blends are not totally satisfactory for all purposes.